The Supreme Court's action caps a series of reversals for Oregon LNG, the developer that proposes to export natural gas from the U.S. drilling boom to Asia. The pipeline would bring gas to the coastal terminal, where it would be superchilled and condensed for shipment.

The Clatsop County commissioners at first approved an initial permit for a 41-mile pipeline to serve the terminal.

But in 2011 a slate of new commissioners rejected it. A trial court and the state Court of Appeals upheld that decision, actions the Supreme Court decided not to review.

"The bottom line is the project does not meet the public safety and salmon protections in Clatsop County," said Brett VandenHeuvel, executive director of the conservation group Columbia Riverkeeper.

Oregon LNG did not immediately respond Friday to phone and email requests for comment on its next steps. It had argued in court that the original county approval should have stood.

The commissioners have another decision in front of them, on the final zoning for the pipeline. County Manager Scott Somers said the commissioners could act on that within a month.

Besides the Warrenton plant, two other LNG plants have been proposed in Oregon. One, also in Clatsop County, was abandoned. Another, in Coos County, remains active.

The projects were originally conceived as import terminals. But the domestic supplies made available through hydraulic fracturing led developers to propose exporting natural gas instead.